Developer for photographic negatives used for printing

ABSTRACT

A developer for photographic films used for half-tone printing which contains at least one compound represented by the following formula in combination with more than 0.008 mols of sulfite ions:   WHEREIN R1 and R3 each represent a hydrogen atom, an alkyl group having one to two carbon atoms, a carboxyl group, an acetyl group having one to two carbon atoms or a hydroxyl group, and R2 and R4 each represent a hydrogen atom, a halogen atom, an alkyl group having one to six carbon atoms, a carboxyl group, a sulfo group, an alkoxy group having one to two carbon atoms, an acetyl group having one to two carbon atoms or a hydroxyalkyl group having one to two carbon atoms.

NEGATIVES USED FOR PRINTING [30] 3 Foreign Application Priority DataDec. 24, 1970 Japan 45/118087 [52] US. Cl 96/66.4, 96/66.3, 96/66 R [51]Int. Cl .L G031: 5/30 [58] Field of Search 96/66, 33, 38, 45

[56] 1 References Cited UNITED STATES PATENTS 1,482,613 2/ 1924 John96/66 R 2,837,430 6/1958 Goldberg 96/66 R 2,877,116 3/1959 Dickersonm.96/66.3 3,128,180 4/1964 Henn et a1. 96/66.4 3,453,109 7/1969 Lee 96/66R 3,490,905 1/ 1970 Blake 96/33 3,557,696 1/1971 Hoover et a1. 96/333,649,281 3/1972 Iwano et a1. 96/66.5

Assignee:

Filed:

Appl. No.: 211,756

Inventors: Haruhiko lwano; Katsumi Hayashi;

Yoo lllljima; Isao Shimamura, all of Minami Ashigara-Machi, Japan FujiPhoto Film Co., Ltd., Minami tates atent 1 [1 11 337769731 lwano et al.51 4, i973 DEVELOPER FOR PHOTOGRAPHICQ Primary Exa miner Norrna n G.-Torchin AssistantExaminer-M. F. Kelley AttorneyRichard C. Sughrue et a1.

[57] ABSTRACT A developer for photographic films used for half-toneprinting which contains at least one compound represented by thefollowing formula in combination with more than 0.008 mols of sulfiteions:

wherein R and R each represent a hydrogen atom, an alkyl group havingone to two carbon atoms, a carboxyl group, an acetyl group having one totwo carbon atoms or a hydroxyl group, and R and R each represent ahydrogen atom, a halogen atom, an alkyl group having one to six carbonatoms, a carboxyl group, a sulfo group, an alkoxy group having one totwo carbon atoms, an acetyl group having one to two carbon atoms or ahydroxyalkyl group having one to two carbon atoms.

8 Claims, No Drawings DEVELOPER FOR PHOTOGRAPHIC NEGATIVES USEDFORPRINTING BACKGROUND OF THE INVENTION 1. Field 'ofthe Invention Thepresent inventionrelates to an infectious developer for producingphotographic films used for printing, and particularly to an infectiousdeveloper having excellent preservability for producing photographicfilms used for printing.

2. Description of the Prior Art Light sensitive photographic elementsused in graphic arts for making half-tone or line images are known(hereafter merely called photographic films used for printing.

Photographic films used for printing are produced, in general, byinfectious development using a lithe-type sensitive element forproducing dot images (hereafter often referred to as meshed dots) orline drawings, or a hard sensitive element having very high contrast andexcellent sharpness. The litho-type sensitive elements used includelitho-films or litho-prin'ting plates. These materials are used forrecording images on an original having a density of continuous gradationby dividing the images into meshed dots which change the variation ofdensity into a variation of area. Litholine film or litholine printingplates are also used for printing an original having line drawings.

In order to divide the image into meshed dots, a glass cross line screenor a contact screen is used. A halftone negative can be produced byprinting images of the original onto the litho-type sensitive elementthrough these screens and carrying out development.

The ideal half tone negative consists of meshed dots having maximumdensity and a background having minimum density. However, no matter howhigh a contrast the sensitive element has, intermediate density areaswhich are called fringe are always formed around the meshed dots, andhave an intermediate density.

Fringe should not occur during plate making'because the quality of theprinting images deteriorates remarkably. Since a line drawing isregarded as a continuation of meshed dot images, intermediate densityareas should not of course, occur on the litholine film or plate.

The developer for producing photographic films used for printing usinglitho-type sensitive elements or other high-contrast sensitive elementsis usually an alkaline. infectious developer which contains adihydroxybenzene type developing agent and an aldehyde-alkalihydrogensulfite addition product as a preservative.

ln infectious developers of this kind, the preservability of thedeveloper is inferior to that of common blackwhite developers since thesulfite ions in the free state are present in a low amount. In adeveloper having a low free sulfite ion concentration'the life of theactivated hydroquinone is kept for a long time, and an in fectiousdevelopment with hydroquinone is successively carried out, by whichprocess rapid development isachieved and images having a high contrastand small fringe are obtained. In infectious developers having a highfree sulfi te ion concentration, since activated hydroquinone isshort-lived and is not accumulated, rapid development is not possibleand images having low contrast and large fringe are obtained. There isthus a reciprocal relationship between'the free sulfite ionconcentration and-the quality of the photographic films usedfor-printing.

It'is'essential 'thatan infectious developer have good preservability.Accordingly, it has been proposed to improve preservability by addingantioxidants other than the sulfites, e.g., it is known to add ascorbicacid to infectious developers (Jap. Pub. No. 28673/69). However,ascorbic acid is unstable and easily decomposes, especially when metalions such as copper ions and iron ions exist in the developer, andthusthe preservability of the developer is poor. Ascorbic acid has thefurther drawbacks that 'itdelays the progress of development and*thequality of the meshed dots deteriorates if it is added in a largeamount. Summary of the Invention One object of the present invention isto provide a developer for photographic films used for printing whichdoes not have a harmful influence upon the quality of the resultingimages and which has excellent preservability.

The present inventors have discovered that the preservability ofinfectious developers is improved without injury to photographicproperties of the infectious developer by the presence of a compoundrepresented by the following formula with more than 0.008 mol ofdissociated sulfite ion in the infectious developer per one liter ofdeveloper:

wherein R, and R each represent a hydrogen atom, an alkyl group havingone to two carbon atoms, a carboxyl group, an acetyl group having one totwo carbon atoms or a hydroxyl group, and R and R each represent ahydrogen atom, a halogen atom, an alkyl group having one to six carbonatoms, a carboxyl group, a sulfo group, an alkoxy group having one to'two carbon atoms, an acetyl group having one to two carbon atoms or ahydroxyalkyl group having one to two carbon atoms.

Examples of compounds represented by the above formula used in thepresent invention include resorcinol, Z-methylresorcinol,S-methylresorcinol, 4- chlororesorcinol, 4-methoxy resorcinol,a-resorcylic acid, B-resorcylic acid, 'y-resorcylic acid, 4-bromoresorcinol, 2,4-dihydroxybenzene sulfonic acid,1,3,5-trihydroxybenzene, 4-n-propyl resorcinol,4,6-ditert-butylresorcinol, o-hydroxyethyl resorcinol, 2,4- dihydroxyacetophenone and 2,6-dihydroxy acetophenone. These compounds arecommonly available.

In the case that the dissociated sulfite ion is not included or isincluded only in a very small amount, good results are not obtained byadding the compounds of the present invention. However, in the case ofan infectious developer containing more than 0.008 mol of sulfite, thepreservability of the developer is remarkably improved by a synergisticeffect with the compounds of the present invention. In this point ofview, the compounds of the present invention are believed to acceleratethe preserving function of the sulfite ions. This function deteriorateswith an increase of the sulfite ion concentration and it is not observedwith best results in the high sulfite ion concentration of 0.2 mole to1.0 mole whichis used for common developers for blackwhite films. Thedecrease in effect might be acceptable to some users, however,especially at value closer to the 0.2 mol figures. On the other hand,the degree of acceleration of the preserving function of the sulfiteions by the compounds of the invention increases with a decrease in thesulfite ion concentration. However, the preservability of the solutionitself lowers because of the absolute decrease in the sulfite ionconcentration. The cooperative effect is very effective in the 0.008 to0.1 mole range of sulfite ion concentration with a more preferred rangebeing 0.01 to 0.08 mole. Therefore, in solutions in which the sulfiteion concentration is low, such as in the infectious developer of theinvention, the cooperative effect of the sulfite ions and the compoundsof the present invention is most effective.

As will be clear from the following examples, the effect of the presentinvention is very large. Although the mechanism of the resorcinolderivatives is not clear, it is believed to be as follows. Thealdehyde-alkali hydrogensulfite addition product included in theinfectious developer releases aldehyde by oxidation of the developerwith a lapse of time and the exhaustion of the developer duringdevelopment. Though the aldehyde reacts with hydroquinone as thedeveloping agent to form a compound which deteriorates the infectiousdeveloping characteristics, the compounds of the present invention reactwith this aldehyde to change it into a photographically harmlessmaterial. The compounds of the present invention thus have the functionof accelerating the rate of development while keeping the infectiousdeveloping property without delaying the progress of development.

The compounds of the present invention can thus be seen to have apeculiar effect. Namely, when the compounds of the present invention areused in an infectious developer, not only is coloring of the solution byoxidation and subsequent deterioration of the treating ability duringstorage or in automatic developing apparatus prevented, but hardening ofhalf-tone gradation by fatigue of the treating solution and increasedfatigue can be prevented.

The developers for photographic films used for printing to which thecompounds of the present invention are added are the common infectiousdevelopers which contain hydroquinone as the developing agent,preferably in an amount offrom about 5 to about 25 g per liter ofdeveloper, water soluble acids, alkalis and salts such as sodiumcarbonate, sodium hydroxide, acetic acid and boric acid as the alkaliagent or a pH buffer agent, an aldehyde-alkali hydrogensulfite additionproduct, ketone-alkali hydrogensulfite addition products, sulfites ortwo or more thereof as antioxidants, and halogenated alkalis as thedeveloping controller. Further, organic antifogging agents such asbenzotriazole and l-phenyl-5-mercapto-tetrazole, polyalkylene oxides,amino compounds and organic solvents such as triethyleneglycol,dimethylformamide, methyl alcohol and cellosolve may be added, ifdesired, in an amount of O to 300 ml per 1 liter of the developer.

The most preferred developer comprises hydroquinone, an addition productand a compound ofthe indicated formula. The presence of sulfite ion isextremely preferred (with a range of 0.008 to 0.2 mole being preferred).The preferred amount of hydroquinone is 5 to 25 g per one liter ofdeveloper, and the preferred range of the addition product is 30 to 60 gper one liter of the developer.

Sulfite salts may be added, if necessary, to provide a sulfite ionconcentration greater than 0.008 mole.

A characteristic of the infectious developer is that the free sulfiteion concentration is low. Thus a sulfite ion buffer such asformaldehyde-sodium hydrosulfite addition product is generally used.Usually, by adding a alkali sulfite such as sodium sulfite in an amountof less than 5 g per liter of the developer'to the sulfite buffer, thefree sulfite ion concentration is controlled. In general, up to 3 g ofsulfite is added, by which the preservability of the developer issomewhat improved, though the quality of meshed dots deteriorates.However, as shown above, such a degree of preservability isinsufficient. However, preservability can be remarkably improved by thecompounds of the present invention.

In the present invention, not only one but two or more of the compoundsof the present invention can be used together.

Although the amount of the compound of the present invention in thedeveloper depends on the composition of the developer and the types ofcompounds present it is usually used in the amount of 2 mg to 10 g perliter of the developer, and 10 mg to 4 g is most preferred.

The compounds of the present invention are generally added at thepreparation of the developer. When the developer is prepared as a liquidor powdery composition and diluted or dissolved at use, it is effectiveto add the compounds to the liquid or powdery composition. In the caseof using a liquid composition, addition to the liquid composition isespecially effective because the preservability of the liquidcomposition is remarkably improved by the addition. Common liquiddeveloper compositions consists of two liquid parts, one part of whichcontains a developing agent and the other part .of which contains analkali agent. The compounds of the invention may be added to eitherpart, but it is more effective to add to the part containing thedeveloping agent. It is also possible to improve the preservability ofthe used developer by adding the compounds of the invention during orafter developing photographic films used for printing, e.g., afteradding the compound to a developer, photographic elements may bedeveloped with the developer, or photographic elements may be developedwith a developer while adding the compound to the developer. Otherwise,after any photographic elements are developed with a developercontaining no compound of the invention, the other photographic elementsare developed with the developer containing the compound.

The preservability of the liquid developer is thus superior, and thestability of the developer after preparation of the infectious developerby diluting is remarkably improved.

As the emulsion of the photographic negative used for printing, commonsilver halide photographic emulsions are used, e.g., those containingsilver chloride, silver bromode, silver bromochloride, silveriodobromide and silver iodobromochloride. Silver bromochloride isparticularly suitable. These silver halides are dispersed in gelatin ora mixture of gelatin and a synthetic high molecular weight polymer toform an emulsion. The emulsion may be chemically sensitized by compoundscontaining unstable sulfur such as sodium thiosulfate and allylthiourea, gold compounds such as complex salts of monovalent gold andthiocyanate, or mixtures thereof. The emulsion may be opticallysensitized by adding color sensitizing agents such as cyanine dyes andmerocyanine dyes. The emulsion may also contain polyalkylene oxides,amino compounds and organic antifogging agents such as benzotriazole.Furthermore, the emulsion'may be hardened by hardeners such asformaldehyde and mucochloric acid, ormay contain surface active agentssuch as saponin in order to facilitate application. These materials arewell knownto the art and are merely added to serve their art recognizedfunction.

The following examples illustrate the present invention in great detail.

EXAMPLE l Commercially available litho films were used and afterphotographing with an exposure wedge for sensitometry through a 150 linemagenta contact screen, the films were developed at 20C using 4 kinds ofdevelopers having the following compositions.

Developer A Sodium carbonate (monohydrate) Formaldehyde-sodiumhydrogensulfite addition product Potassium bromide Hydroquinone Sodiumsulfite Water to make 1 Developer B That obtained by adding g ofS-methyl resorcinol to Developer A. Developer C That obtained by adding2 g of sodium sulfite additionally to Developer -A. Developer D Thatobtained by adding 1 g of L-ascorbic acid to Developer A. The values ofthe photographic properties of the developed films are shown in Table 1.

TABLE 1 Developer Additive Time of Quality Sensitivity developof dotsFresh Elapsed ment solution solution (minutes) A 2% a l00 34 B S-methylresorcinol 2% a 100 90 C Sodium sulfitc 3 c 100 52 D Lascorbic acid 3 a100 50 The time of development was that time required to reach thesensitivity obtained with developing by Developer A for 2 A minutes(this sensitivity was set as 100). The quality of the dots isrepresented by a, b and c, in which a means excellent, b means good andc means bad. Objective measurement of the dot quality are impossible.Therefore, it is usually measured by sight. The term excellent shows dotimages having no fringe and term goodshowsdot images having low fringe,as these measurements are understood by the art. Elapsed solution isthat which is subjected to deterioration by contacting 500 ml of thedeveloper with the air for 5 hours in a cm X cm vat.

As shown in Table l, in control Developer A deterioration with lapse oftime is large, Deterioration of the sensitivity by lapse of time ofDeveloper C, in which 20 g of sodium sulfite was added for comparisonpurposes, is smaller than that of the Developer A but is still large.Deterioration of the sensitivity by lapse of'time of Developer D, inwhich 1.0 g of L-ascorbic acid was added for comparison purposes, is thesame asthatof the Developer C and is insufficient. Deterioration of thesensitivity of lapse of time of Developer B, in which 1.0 g of S-methylresorcinol was added, is the lowest and deterioration of the quality ofdots by the fresh solution was not observed. The solution does noteasily fatigue by treatment, and the quality of dots after treatment ofa number of sensitive elements does not lower greatly.

EXAMPLE 2 Availa blelithofilms were used. After photographing with anexposure wedge for sensitometry through a 150 line magenta contactscreen, the films were developed at 20C using developers prepared from 2kinds of compositions having the following compositions. Developer ESolution 1 Distilled water 60 ml Triethylene glycol 30 mlFormaldehyde-sodium hydrogensulfite addition product 45 g Sodium sulfitel 'g 'Hydroquinone l6 g Distilled water to make 125 ml Solution llDistilled water l00 ml Sodium carbonate (monohydrate) 30 g Sodiumhydroxide 5 g Boric acid 3 g Sodium bromide 2 g Distilled water to make125 ml At use, Solution 1 was added to 750 ml of water and then SolutionII was added thereto to make 1 liter.

-Developers F,G,H,.l and K are prepared by adding the followingcompounds to Developer E.

The results obtained upon development are shown in Table 2.

It will be seen that the deterioration of sensitivity of developerscontaining the compounds of the present invention is small as comparedwith that of developers not containing the compounds.

EXAMPLE 3 The reduction in the amount of hydroquinone in the developerswas determined by charging each solution I of Developers E, F and G intoan air constant temperature bath at 50C for 20 days.

The results are shown in Table 3.

TABLE 3 Developer Amount of hydroquinone remaining (7%) Developer E 87Developer F Developer G 98 From the above results the amount ofhydroquinone in the Solution l, which contains resorcinol and 4-chlororesorcinol does not greatly decrease by the lapse of time, and thedeveloper can endure long periods of preservation.

REFERENCE EXAMPLE.

The same procedure as in Example 1 was carried out but using Developer Linstead of Developer A.

Developer L Sodium carbonate (monohydrate) 50 g Formaldehyde-sodiumhydrogensulfite addition product l5 g Potassium bromide 2 g S-Methylresorcinol l g Hydroquinone 18 g Sulfuric acid (added so pH agreed withthat of Developer A) Water to make 1 liter Upon developing, the qualityof the dots was found to be in class c, and the sensitivity of theelapsed solution deteriorated to such a degree that it could not be usedpractically. Accordingly, when the sulfite ion concentration is verylow, the resorcinol derivatives of the present invention do not exhibita good effect.

What is claimed is:

1. An infectious developer for a light-sensitive silver halide elementcomprising from about 5 to about 25 grams per liter of developer of ahydroquinone compound as the only developing agent, an effective amountof a buffering agent comprising an aldehydealkali hydrogen sulfiteaddition product, from 0.008 to 0.1 mole, per liter of developer, offree sulfite ion and at least one compound representing by the formula:

R: W wherein R, andR each represents a hydrogen atom, an alkyl grouphaving one to two carbon atoms, a carboxyl group, an acetyl group havingone to two carbon atoms or a hydroxyl group, and R and R, eachrepresents a hydrogen atom, a halogen atom, a sulfo group, an alkoxygroup having one to two carbon atoms, an acetyl group having one to twocarbon atoms, or a hydroxyalkyl group having one to two carbon atoms.

2. The developer of claim 1 wherein from 0.01 to 0.08 mole of said freesulfite ions are present per liter of said 'developer.

3. The developer of claim 1 wherein said aldehydealkali hydrogensulfiteaddition product is present in an amount of from 30 to 60 grams perliter of developer.

4. The developer of claim 1 containing from 2 mg to 10 grams per literof the developer of said compound.

5. The developer of claim 1 containing from 10 mg to 4 grams per literof the developer of said compound.

6. The developer of claim 1 wherein said compound is selected from thegroup consisting of resorcinol, 2- methylresorcinol,S-methylre-sorcinol, 4- chlororesorcinol, 4-methoxy resorcinol,a-resorcylic acid, B-resorcylic acid, 'y-resorcylic acid, 4-bromoresorcinol, 2,4-dihydroxybenzene sulfonic acid,1,3,5-trihydroxybenzene, 4-n-propyl resorcinol,4,6-ditert-butylresorcinol, o-hydroxyethyl resorcinol, 2,4- dihydroxyacetophenone and 2,6-dihydroxy acetophenone.

7. An infectious developer for a light-sensitive silver halidephotographic element consisting essentially of from about 5 to about 25grams per liter of developer of hydroquinone as the only developingagent, from 30 to 60 grams per liter of developer of a buffering agentconsisting essentially of an aldehyde-alkali hydrogensulfite additionproduct, from 0.008 to 0.1 mole per liter of developer of free sulfiteion and at least one compound represented by the formula:

Ra --O H wherein R and R each represents a hydrogen atom, an alkyl grouphaving one to two carbon atoms, a earboxyl group, an acetyl group havingone to two carbon atoms or a hydroxyl group, and R and R each representsa hydrogen atom, a halogen atom, a sulfo group, an alkoxy group havingone to two carbon atoms, an acetyl group having one to two carbon atoms,or a hydroxyalkyl group having one to two carbon atoms.

8. The developer of claim 2 wherein said compound is present in saiddeveloper in an amount of from 2 milligrams to 10 grams per liter ofdeveloper.

2. The developer of claim 1 wherein from 0.01 to 0.08 mole of said freesulfite ions are present per liter of said developer.
 3. The developerof claim 1 wherein said aldehyde- alkali hydrogensulfite additionproduct is present in an amount of from 30 to 60 grams per liter ofdeveloper.
 4. The developer of claim 1 containing from 2 mg to 10 gramsper liter of the developer of said compound.
 5. The developer of claim 1containing from 10 mg to 4 grams per liter of the developer of saidcompound.
 6. The developer of claim 1 wherein said compound is selectedfrom the group consisting of resorcinol, 2-methylresorcinol,5-methylre-sorcinol, 4-chlororesorcinol, 4-methoxy resorcinol, Alpha-resorcylic acid, Beta -resorcylic acid, gamma -resorcylic acid,4-bromoresorcinol, 2,4-dihydroxybenzene sulfonic acid,1,3,5-trihydroxybenzene, 4-n-propyl resorcinol,4,6-di-tert-butylresorcinol, o-hydroxyethyl resorcinol, 2,4-dihydroxyacetophenone and 2,6-dihydroxy acetophenone.
 7. An infectious developerfor a light-sensitive silver halide photographic element consistingessentially of from about 5 to about 25 grams per liter of developer ofhydroquinone as the only developing agent, from 30 to 60 grams per literof developer of a buffering agent consisting essentially of analdehyde-alkali hydrogensulfite addition product, from 0.008 to 0.1 moleper liter of developer of free sulfite ion and at least one compoundrepresented by the formula:
 8. The developer of claim 2 wherein saidcompound is present in said developer in an amount of from 2 milligramsto 10 grams per liter of developer.